The present invention relates to a heater core and an air conditioner for an automobile equipped with the same, in which an amount of cooling water introduced into the heater core can be adjusted based on a temperature set by a user, thereby increasing a cooling and heating efficiency.The heater core comprises first and second tanks 210 and 220 which are spaced apart from each other at a predetermined distance; inlet pipe 211 and outlet pipe 212 which are respectively connected to the first tank 210 or second tank 220 and through which cooling water is introduced and discharged; a plurality of tubes 230 of which both ends are respectively fixed between the first and second tanks 210 and 220; a fins 250 which are provided between the tubes 230; a cooling water introduction part 330 which is formed at one side of the inlet pipe 211 and through which the cooling water is introduced; a bypass line 340 which is also formed at one side of the inlet pipe 211 and through which the cooling water is discharged without passing through the heater core H; and a flow rate adjusting means 300 for adjusting an amount of the cooling water introduced into the heater core H.